An Afghan government driver who has disappeared and gone on the run was
confirmed as the main suspect in the murder of two American officers killed
in a high-security command centre in Kabul.

Several hundred Nato advisers and scores of their British counterparts last night remained withdrawn from their posts in Afghan ministries in the wake of the killings over fears other foreigners could be targeted.

The shootings on Saturday afternoon deepened what is already one of the most serious crises of the decade-long Afghan campaign as the country continued to be buffeted by anti-Western protests after the alleged desecration of Korans on an American airbase.

On a sixth day of violent protest, grenades were thrown at an American outpost in Kunduz province, police officials said, wounding six American soldiers.

The Afghan death toll from the nationwide protest now stands at least 30, with more than two hundred wounded.

Two American soldiers were also killed on Thursday, when an Afghan colleague apparently joined protestors and turned his weapon on foreign troops as their base was besieged during a demonstration.

An interior ministry spokesman confirmed police were hunting Abdul Saboor, who worked in the compound where the two officers were found dead after being shot at close range.

The 25-year-old from Parwan province, was described as a trusted driver who had worked at several different ministries and had access to the command and control centre where the officers were found.

Hillary Clinton, United States Secretary of State, said the protests “must stop”.

She said: “We deeply regret the incident that has led to this protest, but we also believe that violence must stop and the hard work for building a more peaceful and secure Afghanistan must continue.”

Hamid Karzai, Afghan president, also appealed for protestors to show restraint as riots continued in Kunduz.

Protests have erupted daily since the first reports that Americans had tried to incinerate religious texts including the Koran after they were sent for disposal from a prison library at Bagram airbase.

American generals and Barack Obama have made a series of apologies for what they say was an inadvertent mistake, but they have failed to soothe Afghan anger.

Mr Karzai said: “It is time to regain and preserve our calm, and not allow our enemies to misuse it.”

A protest in Imam Sahib district of Kunduz broke into a riot, police said, with one civilian killed and fifteen wounded, along with three police.

Seven American military trainers were wounded when a grenade was thrown at their base in the district, Syed Sarwa Hosseini, police spokesman said. The protestors also fired on police with small arms.

A Nato spokesman confirmed there had been an explosion outside the base, but could not give details of casualties.

Using international civilian and military advisers to work alongside local officials is one of the central planks of attempts to bolster the Afghan state before security control is handed over at the end of 2014.

A lengthy withdrawal of hundreds of advisers from Kabul’s ministries would significantly undermine the strategy.

Lt Col Jimmie Cummings, a coalition spokesman, said the senior Nato commander, Gen John Allen, would decide when to reinstall the advisers after an investigation into the interior ministry killings.

He said: “We would like to get them back in as soon as possible, but the answers that come out of the investigation will help us ensure this doesn’t happen again.”